body {
  display:flex;
  margin: 0;
    justify-content: center;
    align-items: center;
    padding: 0 10px;
    box-sizing: border-box;
    min-height: 100vh;
}
.container {
  
    display: flex;
    width: 100%;
}

.preview {
  flex: 1;
  margin-bottom: 20px;
  padding: 20px;
  background: #f5fcff;
  border: 1px solid #d3eeff;
  border-radius: 3px;
  margin: 0;
}

.preview + .preview {
  margin-left: 10px;
}

const previews = ['div', 'pre', 'code']

var userInfo = {name: 'anran758',github: 'https://github.com/anran758'};
var info = JSON.stringify(userInfo, null, 2);

previews.forEach(name=> {
  const preview = document.querySelector('.' + name);
preview.innerHTML = info
})


console.log(preview);